Unit 1 Lesson 3 Scientific Knowledge. … From the Beginning Copyright © Houghton Mifflin Harcourt...

Unit 1 Lesson 3 Scientific Knowledge

… From the Beginning

Copyright © Houghton Mifflin Harcourt Publishing Company

What is science?

• Science is the study of the natural world.

• Scientists study many different things, living and nonliving, from the deepest parts of the ocean to the objects in outer space.

• The natural sciences are divided into three areas: biology or life science, geology or Earth science, and physics or physical science. Chemistry is often included in physical science.


What is science?

• Biology, or life science, is the study of living things.



What is science?

• Geology, or Earth science, is the study of Earth and the processes that shape Earth.



What is science?

• Physical science is the study of nonliving matter and energy.



What does science tell us?

• Scientific knowledge is constantly changing.

• Many things that people consider scientific “facts” are actually the most widely accepted explanations.

• What we learn in science are what most scientists agree are the best explanations about how things happen. They are theories scientists have about the world.



What does science tell us?

• A scientific theory is an explanation supported by a large amount of evidence.

• Theories are what most scientists agree to be the best explanations based upon what we now know.



Not a Theory—It’s a Law!


How do scientific theories differ from laws?

• The words law and theory have specific meanings in science.

• A scientific law is a description of a specific relationship under given conditions in the natural world.

• Scientific laws describe the way the world works. They hold anywhere in the universe.


What does Boyle’s Law describe?



• Boyle’s law describes the relationship between the volume and pressure of a gas that is kept at a constant temperature.

• Boyle’s law states that at a constant temperature, when the pressure of a gas is increased, its volume decreases. When the pressure of a gas decreases at a constant temperature, its volume increases.

What does Boyle’s Law describe?



How can Boyle’s Law be graphed?



A graph for Boyle’s Law shows that a pressure of a gas varies inversely with its volume at constant temperature (curved line)

How do scientific theories differ from laws?

• A scientific theory is a well-supported explanation of nature.

• Scientific theories are supported by many pieces of evidence.

• Theories help us understand and explain the laws we observe.



What is the Cell Theory?

• The cell theory states that living things are made up of cells that perform the basic functions of life.



What’s Your Evidence?


Where do scientists get their evidence?

• Scientists are curious. They look at everything going on around them, ask questions, and collect information to answer these questions.

• Scientific knowledge is based on empirical evidence.

• Empirical evidence is all the measurements and data scientists gather in support of a scientific explanation.



• Scientists gather evidence in many places. Some do fieldwork, and others do laboratory work.

• Fieldwork is work done outdoors or where conditions cannot be controlled.

• Fieldwork gives scientists the opportunity to collect data in an original setting. Biologists and geologists do fieldwork.




• In a laboratory, scientists have the opportunity to collect data in a controlled environment.

• Most experiments are conducted in laboratories. In an experiment, scientists try to see what happens under certain conditions.

• Laboratories come in many varieties. They can be in the ocean or in the sky.



The Debate Continues


How do scientific ideas change?

• Scientific knowledge is what scientists think are the most-likely explanations for what we see. Over time, these explanations can change.

• Scientific ideas and explanations change when new evidence is found or when someone gives a better explanation of the old evidence.


The Debate Continues


How has the model of the atom changed?

• The theory of atoms is a good example of how new evidence can modify an established theory.


How do scientific ideas change?

• Scientists collaborate and share ideas. Often, many brains are better than one when solving a puzzle.

• Scientists regularly gather at meetings to discuss and debate ideas. Many ideas are not accepted at first.

• This rigorous evaluation ensures that scientific knowledge is solidly supported.



Unit 1 Lesson 3 Scientific Knowledge. … From the Beginning Copyright © Houghton Mifflin Harcourt...

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